RFC 2163 (rfc2163) - Page 2 of 26
Using the Internet DNS to Distribute MIXER Conformant Global Address Mapping (MCGAM)
Alternative Format: Original Text Document
RFC 2163 MIXER MCGAM January 1998 1. Introduction The connectivity between the Internet SMTP mail and other mail services, including the Internet X.400 mail and the commercial X.400 service providers, is assured by the Mail eXchanger (MX) record information distributed via the Internet Domain Name System (DNS). A number of documents then specify in details how to convert or encode addresses from/to RFC 822 style to the other mail system syntax. However, only conversion methods provide, via some algorithm or a set of mapping rules, a smooth translation, resulting in addresses indistinguishable from the native ones in both RFC 822 and foreign world. MIXER describes a set of mappings (MIXER Conformant Global Address Mapping - MCGAM) which will enable interworking between systems operating the CCITT X.400 (1984/88/92) Recommendations and systems using using the RFC 822 mail protocol, or protocols derived from RFC 822. That document addresses conversion of services, addresses, message envelopes, and message bodies between the two mail systems. This document is concerned with one aspect of MIXER: the mechanism for mapping between X.400 O/R addresses and RFC 822 domain names. As described in Appendix F of MIXER, implementation of the mappings requires a database which maps between X.400 O/R addresses and domain names; in RFC 1327 this database was statically defined. The original approach in RFC 1327 required many efforts to maintain the correct mapping: all the gateways needed to get coherent tables to apply the same mappings, the conversion tables had to be distributed among all the operational gateways, and also every update needed to be distributed. The concept of mapping rules distribution and use has been revised in the new MIXER specification, introducing the concept of MIXER Conformant Global Address Mapping (MCGAM). A MCGAM does not need to be globally installed by any MIXER conformant gateway in the world any more. However MIXER requires now efficient methods to publish its MCGAM. Static tables are one of the possible methods to publish MCGAM. However this static mechanism requires quite a long time to be spent modifying and distributing the information, putting heavy constraints on the time schedule of every update. In fact it does not appear efficient compared to the Internet Domain Name Service (DNS). More over it does not look feasible to distribute the database to a large number of other useful applications, like local address converters, e-mail User Agents or any other tool requiring the mapping rules to produce correct results. Allocchio Standards Track
